While I can't speak for your area I frequently sail on the Mississippi where it widens out into a large Lake on the MN / WI border. It's a great place to sail and with your certs you'll be fine in that boat. If you are sailing in the main navigable channel though and not in a lake where the river widens you may find the tacking to become boring and with the current you might not always make great headway up river. Also you'll want to be on the lookout for barge traffic as they come up the channel and for any wing dams (submerged dams out of the main channel) if they have any in the section of the river you sail on. There is a group in Lacrosse WI that sails a lot of O'days on the river and they seem to like them.